The present invention relates to antiperspirant compositions which contain an aluminum or aluminum-zirconium antiperspirant salt and a water soluble calcium salt. It also relates to a method of inhibiting perspiration by topically applying an effective amount of such an antiperspirant composition to the skin.
Antiperspirant compositions containing aluminum or aluminum-zirconium antiperspirant salts are well-known and have been used for many years. There has been an ongoing effort to improve the antiperspirant efficacy of such compositions. Currently the most efficacious antiperspirant compositions contain the so-called "enhanced efficacy" aluminum or aluminum-zirconium antiperspirant salts suspended in an anhydrous carrier. The enhanced efficacy aluminum and aluminum-zirconium antiperspirant salts are well known and are described, for example, in GB 2,048,229 and U.S. Pat. No. 4,775,528. These salts are generally made by heat treating a relatively dilute aqueous solution of the aluminum salt (e.g. about 10% by weight) to increase its HPLC peak 4 to peak 3 ratio, adding zirconium salt if an aluminum-zirconium salt is desired, then spray drying to a powder. These salts typically have an HPLC peak 4 to peak 3 area ratio of 0.7 or higher, with at least 70% of the aluminum contained in said peaks. Beyond using these enhanced efficacy forms of aluminum and aluminum-zirconium salts, however, it has not been possible to provide any significant boost to the efficacy (or sweat inhibition) of present day antiperspirant compositions.
In U.S. Pat. No. 2,571,030 there are disclosed calcium aluminum basic chloride antiperspirant salts which have less of a deteriorating effect on fabric than aluminum basic chloride (chlorhydroxide). These salts are made by reacting calcium carbonate with aluminum chlorhydroxide or with aluminum chloride and aluminum powder, or by adding calcium chloride dihydrate to aluminum chlorhydroxide. This patent suggests that the antiperspirant salts may have 0.2 to 15 parts by weight of calcium for every 100 parts by weight of aluminum. The salts are used in aqueous form to make cream emulsions.
In U.S. Pat. No. 3,979,510 there are disclosed aluminum-zirconium antiperspirant compositions containing aluminum buffering agents to raise the pH. The aluminum buffering agents may include well-known antacid complexes such as hydrated magnesium aluminum sulfate as well as the co-precipitates of aluminum hydroxide with magnesium or calcium carbonate. Examples VIII and XI describe the preparation of Al--Zr salt complexes containing 0.6% and 0.2% calcium respectively. In U.S. Pat. No. 3,996,346 there are disclosed deodorant and antiperspirant compositions which contain zinc oxide and calcium hydroxide, but which do not contain any aluminum salts.
In U.S. Pat. No. 3,998,788 there are disclosed aluminum-zirconium antiperspirant complexes containing trace amounts of alkaline earth metal salts, particularly calcium or magnesium or both, and preferably magnesium. Generally, the complexes will contain one part alkaline earth metal to 30-1000 parts by weight of aluminum plus zirconium. A solution containing 5-15% aluminum plus zirconium (roughly 10 to 30% active) will contain about 0.001-0.1% alkaline earth metal. No composition containing calcium is exemplified.
In U.S. Pat. No. 4,017,599 there are disclosed aluminum-zirconium antiperspirant complexes buffered with salts of amino acids including hydroxy aluminum glycinates and alkaline and alkaline earth glycinates. This patent suggests that the various alkaline salts, including sodium, potassium, ammonium, magnesium and calcium, are equally suitable. Example V of this patent describes a solid aluminum-zirconium hydroxybromide complex containing 2.24% Al, 31.2% Zr, 28.6% Br, 4.26% glycine, and 1.10% Ca. The extremely low Al:Zr ratio of this salt places it well outside the current FDA monograph. In U.S. Pat. No. 4,021,536 there are disclosed astringent zirconium compositions containing a magnesium salt, such compositions having a zirconium to magnesium content, expressed as oxides, of about 30:1 to 1:1. The examples of this patent do not disclose any compositions containing aluminum or calcium.
In CA 1,068,215 there is disclosed a high pay-off antiperspirant stick comprising 5-20% magnesium stearate, 1-5% calcium carbonate, 0-1% mineral oil, 0.1-5% glycine, 0.01-1% deodorant agent, 20-77.8% aluminum chlorhydroxide, 1-10% kaolin, 10-40% rice starch, 0-3% water, and 0.001-1% perfume. The antiperspirant stick is made by making a first blend of the aluminum salt with mineral oil, making a second blend of the rice starch and water, making a third blend of the remaining ingredients, then mixing the three blends and compressing the mixture into a stick.
In WO 96/19228 there are described topical compositions which contain a topical vehicle, a skin irritating ingredient and an anti-irritant amount of an aqueous soluble divalent calcium cation in an amount of 10 mM to 3000 mM. This publication generally suggests a wide variety of topical compositions including sunscreens, insect repellants, shave creams, depilatories, shampoos, permanent wave and hair straightener products, detergents, drug products, antiperspirant and deodorant products, lozenges, mouthwashes, suppositories, etc. No antiperspirant compositions are exemplified, nor is there any suggestion that the efficacy of antiperspirant compositions may be improved by the addition of calcium salts.
In U.S. Pat. No. 5,346,694 there are disclosed antiperspirant compositions in the form of gel sticks which contain a gelling agent stabilizer with a specified pK.sub.a. The stabilizer may be a basic metallic salt of certain carboxylic acids. Suitable salt forming cations include sodium, potassium, lithium, magnesium, calcium and zinc. The preferred salts are sodium and potassium benzoate and octanoate. In U.S. Pat. No. 5,534,246 there are disclosed clear water-in-oil antiperspirant emulsions in which the refractive indices of the oil and water phases are matched. A variety of refractive index adjusting compounds are disclosed, one of which is calcium chloride. Examples 5 and 6 disclose aqueous solutions containing, respectively, 32.94% and 36.25% aluminum chlorohydrate and 11.94% and 6.88% calcium chloride.
In U.S. Pat. No. 5,676,936 there are disclosed alcohol based antiperspirant compositions in which the antiperspirant salt is suspended in an alcohol carrier. Prior to addition of the antiperspirant salt, an anti-dissolution agent is incorporated into the alcohol to inhibit dissolution of the antiperspirant salt in the alcohol. The anti-dissolution agent may be a compound having a basic nitrogen function or a basic oxygen function. Compounds having a basic nitrogen function include amino acids. Compounds having a basic oxygen function include inorganic bases such as sodium, potassium, lithium, calcium and magnesium hydroxide.
Michniak, Int'l. J. Cosm. Sci. 3, 29-36 (1981), describes the effect of various polyvalent cations on sweat production using a rat foot pad test. Calcium chloride solution was found to promote sweating. Calcium chloride was also found to reduce the effectiveness of aluminum, lanthanum and zirconium solutions.
It would be highly desirable to provide antiperspirant compositions which are more efficacious--that is, inhibit perspiration to a greater degree--than those compositions which are currently available.